docs: def blackbody_wn_rad2temp(wavenumber, radiance):
      """Derive brightness temperatures from radiance using the Planck 
      function. Wavenumber space"""
  
      if np.isscalar(radiance):
          rad = np.array([radiance, ], dtype='float64')
      else:
          rad = np.array(radiance, dtype='float64')
      if np.isscalar(wavenumber):
          wavnum = np.array([wavenumber, ], dtype='float64')
      else:
          wavnum = np.array(wavenumber, dtype='float64')
  
      const1 = H_PLANCK * C_SPEED / K_BOLTZMANN
      const2 = 2 * H_PLANCK * C_SPEED**2
      res = const1 * wavnum / np.log(np.divide(const2 * wavnum**3, rad) + 1.0)
  
      shape = rad.shape
      resshape = res.shape
  
      if wavnum.shape[0] == 1:
          if rad.shape[0] == 1:
              return res[0]
          else:
              return res[::].reshape(shape)
      else:
          if rad.shape[0] == 1:
              return res[0, :]
          else:
              if len(shape) == 1:
                  return np.reshape(res, (shape[0], resshape[1]))
              else:
                  return np.reshape(res, (shape[0], shape[1], resshape[1]))